Pulverized fuel feeder



Nov. 19, 1935. c. M. BUCK PULVERI'ZED FUEL FEEDER F iled Nov. 12. 1930 w n u Z n Q ATTORNEYS to produce uniformity of feed.

Patented Nov. 19, 1935 UNITED STATES aozrru PATENT, o

FFl-CE mvhmznn FUEL l neman Charles M. Buck,

Application November 12,

Brooklyn, N. Y. roam-serial No; 495,006

v r cm. (01. soc-3 s) This invention relates to the feeding of pulverized material such, for example, as pulverized coal to a burner.

Qne of the primary objects of the invention is invention to obtain uniformity of feed ,with thorough admixture of-the coal and air so that the coal remains in suspension. while being delivered to the burner nozzle and stratification is'avoided.

. tially broken out.

Other and more specific objects and advanv .tages will appear hereinafter in the description of thepreferred embodiment of myinvention which I have illustrated in' the accompanyin drawing whereln- Fig. l is an end elevation of the apparatus par- Fig. 2 is a vertical sectionthrough the device of Fig. 1.

Fig. 3 is a perspective view illustrating a detail of the invention, and

Fig. 4 is a fragmentary perspective view another detail of the invention. Referring now to the drawing the reference numeral 1 indicates a hopper adapted to receive a charge of pulverized material such as coal. It has a discharge throatl into the bottom of which is a narrow slot 9 of considerable length, such slot constituting the discharge orifice from the throat. Immediately above the discharge orifice I provide a toothed roller l0 which is of a length substantiaily corresponding to that of the discharge orifice 9 and slightly less than the longitudinal length of the discharge throat. The toothed roller Ill is rotated by any preferred means such as the gearing ll diagrammatically indicated.

Immediately below the orifice is a laterally extending conduit arfwmch is in. the form of a fiattened tube, corresponding in width with the length of the orifice. This conduit has a division' wall I: which terminates approximately in line with the leading edge of the discharge orifice and which provides a shallow but wide channel or passage ll through which air is induced, as wm further appear. The division wall also provides in 'con iunction with other parts an intake channel or passage l to the conduit I! for pressure, air whibh is supplied by the fan It. with the fan in operation'there is a blast ofair delivered to the conduit I! in the lower por I tion-thereofwThis blast of air produces a low.

- screens Aand B in thehopper, the former. being hopp flciently so that their upper ends are above the 50 pressure area adjacent the orifice and the inner end of the channel N, in consequence of which the coal is drawn through the discharge orifice and there is also drawn stream of inducted air through the channel It, the intake end-of which. is open to the atmosphere. The induced air,-of course, travels at lower velocity than the blast air, in consequence of which eddles are set up which produce. thorough admixture oi the coal and airand maintain the coal in suspension so 10 that stratification does not take placeand the coal is delivered to the nozzle I! in thoroughly admixed condition, notwithstanding that relatively low pressures may be employed for the blast air. The nozzle delivers the mixture in theform of, a wide 15 sheet.

There is a tendency of the coal to pack, particularly in the'lower portion of the hopper because sized by reasonof sucking out of air through the discharge orifice of the throat. Due to packing, V

arching occurs and the feed of coal may be interrupted entirely or 'may otherwise become ununiform. V 25 I overcome these diihculties by placing: two

preferably located immediately above the discharge throat and the latter some distance thereabove. These screens comprise two end rods: I830 and I! with cross rods M as shown in Fig. '3' which illustrates the upper screen 13., The rods 20 are preferably curved. The screen thus presents a series of parallel openings. I have found this form of screen much better than a screen in 35 which: there are, in addition to the rods 20, other cross rods paralleling the rods l8 and It. The screens function to support some of the weight of the coal so that the entire head of the coal is not effective in the lowerportion of the hopper 40 to produce packing.- I t I Inaddition I support, upon the lower screen, an aerating device C which comprises a bottom portion 2| open at its lower face and the pipes 22, of which there are any'desired number, which 45 rise thereabove and communicate at their lower ends with the interior of the bottom portion 2| and at their-upper endsjwith the interior of the The pipes 22 extend upwardly sufnormal level of coal in the hopper. The suction at the discharge orifice t hereinbefore referred to tends to cause a slight flow of air downward through the pipes 22, in consequence of which thereis an air supply to the upper end of the discharge throat which results in maintaining the coal in that region aerated. v i

In consequence I find that I am enabled to maintain uniformity of feed.

The invention is particularly useful in connection with burners in which all or substantially all of the air for combustion is supplied through the burner. In the embodiment shown the fan l6 and the induced air inlet i4 provides such combustion air. The device may be considered as a combined feeder and burner when a burner is associated therewith.

The aerating device also serves to equalize pressure at the throat, and makes it possible to dispense with the induced air passage H.

I claim:-

1. In equipment for handling pulverized fuel, a bin adapted to receive a charge of pulverized fuel, the bin having a discharge opening in the lower part thereof, conveyormeans adjacent said opening for carrying away pulverized fuel discharged through the opening and for ultimate delivery of the fuel to a fuel burner, and means for reducing arching or packing of the pulverized fuel in the bin at a point above saidopening, including a plurality of bars extending across the .Jacent said opening for carrying away pulverized material discharged through the opening, and means for reducing arching or packing of the pulverized material in the bin at a point above said opening which combines grid elements extending across the bin in the region of the discharge opening, whereby to give support to the pulverized material in an upper portion of the bin and to break up the mass as it falls to replace the material withdrawn from the bin, and an air supply conduit projecting into the pulverized material in the bin and having an air discharge opening at a point adjacent to the grid members, whereby to provide air for mixture with the coal as its mass breaks up in falling through the grid members.

CHARLES M. .BUCK. 

